1. Field of the Invention
The present invention relates generally to a wafer securing device and method, and more particularly to a wafer securing device and method utilizing vacuum suction force to secure a planar plate on a wafer.
2. Description of the Prior Art
In semi-conductor manufacturing processes, it is often necessary to secure the relative positions of two chips in order to proceed with the subsequent steps. If it is desirable to adhere a planar plate to a wafer, the steps are: (1) coating the wafer with an adhesive; (2) placing the planar plate on the wafer; (3) securing the planar plate and the wafer; (4) transferring the secured wafer and planar plate to a heating plate for heating and pressure application; and (5) removing the securing device. With the fast advancement in the making of semi-conductors, the degree of integration is becoming more and more important. The distance between elements and elements is gradually reduced. Hence, the securing step becomes very important. When the planar plate is placed on the wafer by precision positioning, any improper securing will result in displacement during the transfer process so that the elements can no longer be used, which will increase faulty product rate.
One conventional securing method is to utilize a clamping device. Referring to FIG. 1, which is a schematic view of the prior method of securing the wafer, a planar plate 2 is placed on a wafer 1 and a clamping device 3 is used to secure the relative position of the planar plate 2 and the wafer 1. The clamping device includes a base 31, clamping portions 32, pressure cylinders 33, and air supply tubes 34. The air supply tubes 34 are used to control entry of air into the pressure cylinders 33 so that the clamping portions 32 above press downwardly to secure the planar plate 2 and the wafer 1. Such device may utilize the air flow to control the clamping portions 32 to exert a pressure on the planar plate 2 and the wafer 1 so as to exert a suitable clamping force on wafers of varying strength. Use of a simple clamping tool to secure the planar plate 2 and the wafer 1 overlooks the importance of controlling the clamping force. Such clamping device may lead to interference of a non-positive force due to improper application of force, so that displacement occurs between the planar plate 2 and the wafer 1. If the force exerted by the clamping portions at the sides is not uniform, slanting may result and the planar plate 2 and the wafer 1 cannot be properly positioned. Besides, the step of precision positioning becomes a waste of effort. Therefore, trying to secure wafers by pressure application is not ideal.